/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software  Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2005 by the Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup modifiers
 */

#include "BLI_utildefines.h"

#include "BLI_math.h"

#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"

#include "BKE_action.h"
#include "BKE_editmesh.h"
#include "BKE_library.h"
#include "BKE_library_query.h"
#include "BKE_mesh.h"
#include "BKE_modifier.h"
#include "BKE_deform.h"
#include "BKE_colortools.h"

#include "DEG_depsgraph_query.h"

#include "MEM_guardedalloc.h"

#include "MOD_util.h"

static void initData(ModifierData *md)
{
  HookModifierData *hmd = (HookModifierData *)md;

  hmd->force = 1.0;
  hmd->curfalloff = curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
  hmd->falloff_type = eHook_Falloff_Smooth;
  hmd->flag = 0;
}

static void copyData(const ModifierData *md, ModifierData *target, const int flag)
{
  const HookModifierData *hmd = (const HookModifierData *)md;
  HookModifierData *thmd = (HookModifierData *)target;

  modifier_copyData_generic(md, target, flag);

  thmd->curfalloff = curvemapping_copy(hmd->curfalloff);

  thmd->indexar = MEM_dupallocN(hmd->indexar);
}

static void requiredDataMask(Object *UNUSED(ob),
                             ModifierData *md,
                             CustomData_MeshMasks *r_cddata_masks)
{
  HookModifierData *hmd = (HookModifierData *)md;

  /* ask for vertexgroups if we need them */
  if (hmd->name[0] != '\0') {
    r_cddata_masks->vmask |= CD_MASK_MDEFORMVERT;
  }
  if (hmd->indexar != NULL) {
    /* TODO check which origindex are actually needed? */
    r_cddata_masks->vmask |= CD_MASK_ORIGINDEX;
    r_cddata_masks->emask |= CD_MASK_ORIGINDEX;
    r_cddata_masks->pmask |= CD_MASK_ORIGINDEX;
  }
}

static void freeData(ModifierData *md)
{
  HookModifierData *hmd = (HookModifierData *)md;

  curvemapping_free(hmd->curfalloff);

  MEM_SAFE_FREE(hmd->indexar);
}

static bool isDisabled(const struct Scene *UNUSED(scene),
                       ModifierData *md,
                       bool UNUSED(useRenderParams))
{
  HookModifierData *hmd = (HookModifierData *)md;

  return !hmd->object;
}

static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)
{
  HookModifierData *hmd = (HookModifierData *)md;

  walk(userData, ob, &hmd->object, IDWALK_CB_NOP);
}

static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphContext *ctx)
{
  HookModifierData *hmd = (HookModifierData *)md;
  if (hmd->object != NULL) {
    if (hmd->subtarget[0]) {
      DEG_add_bone_relation(
          ctx->node, hmd->object, hmd->subtarget, DEG_OB_COMP_BONE, "Hook Modifier");
    }
    DEG_add_object_relation(ctx->node, hmd->object, DEG_OB_COMP_TRANSFORM, "Hook Modifier");
  }
  /* We need own transformation as well. */
  DEG_add_modifier_to_transform_relation(ctx->node, "Hook Modifier");
}

struct HookData_cb {
  float (*vertexCos)[3];

  MDeformVert *dvert;
  int defgrp_index;

  struct CurveMapping *curfalloff;

  char falloff_type;
  float falloff;
  float falloff_sq;
  float fac_orig;

  unsigned int use_falloff : 1;
  unsigned int use_uniform : 1;

  float cent[3];

  float mat_uniform[3][3];
  float mat[4][4];
};

static float hook_falloff(const struct HookData_cb *hd, const float len_sq)
{
  BLI_assert(hd->falloff_sq);
  if (len_sq > hd->falloff_sq) {
    return 0.0f;
  }
  else if (len_sq > 0.0f) {
    float fac;

    if (hd->falloff_type == eHook_Falloff_Const) {
      fac = 1.0f;
      goto finally;
    }
    else if (hd->falloff_type == eHook_Falloff_InvSquare) {
      /* avoid sqrt below */
      fac = 1.0f - (len_sq / hd->falloff_sq);
      goto finally;
    }

    fac = 1.0f - (sqrtf(len_sq) / hd->falloff);

    /* closely match PROP_SMOOTH and similar */
    switch (hd->falloff_type) {
#if 0
      case eHook_Falloff_None:
        fac = 1.0f;
        break;
#endif
      case eHook_Falloff_Curve:
        fac = curvemapping_evaluateF(hd->curfalloff, 0, fac);
        break;
      case eHook_Falloff_Sharp:
        fac = fac * fac;
        break;
      case eHook_Falloff_Smooth:
        fac = 3.0f * fac * fac - 2.0f * fac * fac * fac;
        break;
      case eHook_Falloff_Root:
        fac = sqrtf(fac);
        break;
      case eHook_Falloff_Linear:
        /* pass */
        break;
#if 0
      case eHook_Falloff_Const:
        fac = 1.0f;
        break;
#endif
      case eHook_Falloff_Sphere:
        fac = sqrtf(2 * fac - fac * fac);
        break;
#if 0
      case eHook_Falloff_InvSquare:
        fac = fac * (2.0f - fac);
        break;
#endif
    }

  finally:
    return fac * hd->fac_orig;
  }
  else {
    return hd->fac_orig;
  }
}

static void hook_co_apply(struct HookData_cb *hd, const int j)
{
  float *co = hd->vertexCos[j];
  float fac;

  if (hd->use_falloff) {
    float len_sq;

    if (hd->use_uniform) {
      float co_uniform[3];
      mul_v3_m3v3(co_uniform, hd->mat_uniform, co);
      len_sq = len_squared_v3v3(hd->cent, co_uniform);
    }
    else {
      len_sq = len_squared_v3v3(hd->cent, co);
    }

    fac = hook_falloff(hd, len_sq);
  }
  else {
    fac = hd->fac_orig;
  }

  if (fac) {
    if (hd->dvert) {
      fac *= defvert_find_weight(&hd->dvert[j], hd->defgrp_index);
    }

    if (fac) {
      float co_tmp[3];
      mul_v3_m4v3(co_tmp, hd->mat, co);
      interp_v3_v3v3(co, co, co_tmp, fac);
    }
  }
}

static void deformVerts_do(HookModifierData *hmd,
                           const ModifierEvalContext *UNUSED(ctx),
                           Object *ob,
                           Mesh *mesh,
                           float (*vertexCos)[3],
                           int numVerts)
{
  Object *ob_target = hmd->object;
  bPoseChannel *pchan = BKE_pose_channel_find_name(ob_target->pose, hmd->subtarget);
  float dmat[4][4];
  int i, *index_pt;
  struct HookData_cb hd;

  if (hmd->curfalloff == NULL) {
    /* should never happen, but bad lib linking could cause it */
    hmd->curfalloff = curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
  }

  if (hmd->curfalloff) {
    curvemapping_initialize(hmd->curfalloff);
  }

  /* Generic data needed for applying per-vertex calculations (initialize all members) */
  hd.vertexCos = vertexCos;
  MOD_get_vgroup(ob, mesh, hmd->name, &hd.dvert, &hd.defgrp_index);

  hd.curfalloff = hmd->curfalloff;

  hd.falloff_type = hmd->falloff_type;
  hd.falloff = (hmd->falloff_type == eHook_Falloff_None) ? 0.0f : hmd->falloff;
  hd.falloff_sq = SQUARE(hd.falloff);
  hd.fac_orig = hmd->force;

  hd.use_falloff = (hd.falloff_sq != 0.0f);
  hd.use_uniform = (hmd->flag & MOD_HOOK_UNIFORM_SPACE) != 0;

  if (hd.use_uniform) {
    copy_m3_m4(hd.mat_uniform, hmd->parentinv);
    mul_v3_m3v3(hd.cent, hd.mat_uniform, hmd->cent);
  }
  else {
    unit_m3(hd.mat_uniform); /* unused */
    copy_v3_v3(hd.cent, hmd->cent);
  }

  /* get world-space matrix of target, corrected for the space the verts are in */
  if (hmd->subtarget[0] && pchan) {
    /* bone target if there's a matching pose-channel */
    mul_m4_m4m4(dmat, ob_target->obmat, pchan->pose_mat);
  }
  else {
    /* just object target */
    copy_m4_m4(dmat, ob_target->obmat);
  }
  invert_m4_m4(ob->imat, ob->obmat);
  mul_m4_series(hd.mat, ob->imat, dmat, hmd->parentinv);
  /* --- done with 'hd' init --- */

  /* Regarding index range checking below.
   *
   * This should always be true and I don't generally like
   * "paranoid" style code like this, but old files can have
   * indices that are out of range because old blender did
   * not correct them on exit editmode. - zr
   */

  if (hmd->force == 0.0f) {
    /* do nothing, avoid annoying checks in the loop */
  }
  else if (hmd->indexar) { /* vertex indices? */
    const int *origindex_ar;

    /* if mesh is present and has original index data, use it */
    if (mesh && (origindex_ar = CustomData_get_layer(&mesh->vdata, CD_ORIGINDEX))) {
      for (i = 0, index_pt = hmd->indexar; i < hmd->totindex; i++, index_pt++) {
        if (*index_pt < numVerts) {
          int j;

          for (j = 0; j < numVerts; j++) {
            if (origindex_ar[j] == *index_pt) {
              hook_co_apply(&hd, j);
            }
          }
        }
      }
    }
    else { /* missing mesh or ORIGINDEX */
      for (i = 0, index_pt = hmd->indexar; i < hmd->totindex; i++, index_pt++) {
        if (*index_pt < numVerts) {
          hook_co_apply(&hd, *index_pt);
        }
      }
    }
  }
  else if (hd.dvert) { /* vertex group hook */
    for (i = 0; i < numVerts; i++) {
      hook_co_apply(&hd, i);
    }
  }
}

static void deformVerts(struct ModifierData *md,
                        const struct ModifierEvalContext *ctx,
                        struct Mesh *mesh,
                        float (*vertexCos)[3],
                        int numVerts)
{
  HookModifierData *hmd = (HookModifierData *)md;
  Mesh *mesh_src = MOD_deform_mesh_eval_get(ctx->object, NULL, mesh, NULL, numVerts, false, false);

  deformVerts_do(hmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);

  if (!ELEM(mesh_src, NULL, mesh)) {
    BKE_id_free(NULL, mesh_src);
  }
}

static void deformVertsEM(struct ModifierData *md,
                          const struct ModifierEvalContext *ctx,
                          struct BMEditMesh *editData,
                          struct Mesh *mesh,
                          float (*vertexCos)[3],
                          int numVerts)
{
  HookModifierData *hmd = (HookModifierData *)md;
  Mesh *mesh_src = MOD_deform_mesh_eval_get(
      ctx->object, editData, mesh, NULL, numVerts, false, false);

  deformVerts_do(hmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);

  if (!ELEM(mesh_src, NULL, mesh)) {
    BKE_id_free(NULL, mesh_src);
  }
}

ModifierTypeInfo modifierType_Hook = {
    /* name */ "Hook",
    /* structName */ "HookModifierData",
    /* structSize */ sizeof(HookModifierData),
    /* type */ eModifierTypeType_OnlyDeform,
    /* flags */ eModifierTypeFlag_AcceptsCVs | eModifierTypeFlag_AcceptsLattice |
        eModifierTypeFlag_SupportsEditmode,
    /* copyData */ copyData,

    /* deformVerts */ deformVerts,
    /* deformMatrices */ NULL,
    /* deformVertsEM */ deformVertsEM,
    /* deformMatricesEM */ NULL,
    /* applyModifier */ NULL,

    /* initData */ initData,
    /* requiredDataMask */ requiredDataMask,
    /* freeData */ freeData,
    /* isDisabled */ isDisabled,
    /* updateDepsgraph */ updateDepsgraph,
    /* dependsOnTime */ NULL,
    /* dependsOnNormals */ NULL,
    /* foreachObjectLink */ foreachObjectLink,
    /* foreachIDLink */ NULL,
    /* foreachTexLink */ NULL,
    /* freeRuntimeData */ NULL,
};
